# Question #85af2

##### 1 Answer

#### Explanation:

In terms of actually understanding, I find it is easier to look at the reverse process first, namely differentiation. We know for example that, for some constant

(Incidentally, this follows from the **more general conclusion** that:

It follows from integrating

Or, by realising that in the red term the integration and differentiation "cancel out" (by the Fundamental Theorem of Calculus), and then reversing the order:

Or, moving the constant across:

Then, adding a new constant

So with

That's all rather mechanical and somewhat dry, but I think it might help find a way of doing these that doesn't involve much memory.